In vitro study on 144 extracted teeth. According to the ISO standard ISO / TR 11405, teeth were collected, stored, molded, divided into 12 groups, 12 teeth each. They were treated with 3 types of adhesive systems in 4 different operating conditions. Composite rollers simulating orthodontic brackets have been installed. 144 shear of composite rollers was done on the ripper. Shear force is marked in kg (kilograms) with an accuracy of 100g ( grams). The largest and smallest sample results in each group were discarded. We divided 120 voltages into 12 groups. We used Opti Bond Solo Plus (two-component adhesive), Opti Bon Universal and Zip Bond Universal. Control bonding and mold preparation were done according to ISO standard (control group). In the conditions of naturally curved machine-treated enamel, we performed bonding in dry and contaminated conditions (moisture, blood). Breaking stresses are expressed in kg (kilograms), and converted into N (Newtons) and MPa (mega Pascals). Mean values are statistically processed, tabulated and graphically presented. The ARI index is also shown. The��obtained data were compared with literal data. Significant differences between the samples were also shown. In case of contamination, we suggest working with Opti Bond Solo Plus and ZIP Bond Universal. We also proposed a protocol for intraoperative bonding of orthodontic brackts on the enamel of non-erupted teeth.